Gentlemens:

I have recently acquired an early Gibb Farquharson action that is alleged to have been originally chambered in .577-450, and the extractor dimensions support this. The .577-.450 is an anomaly in Gibbs rifles and a chambering that doesn't interest me. Only the action exists and from the two digit serial number I would estimate a born on date in the late 70's

From what I can gather it seems that about this time Gibbs offered his Gibbs .461 #1 and #2, the .500 Express and the .577 2-3/4". Of these the one that interests me the most is the .577.

Howsomever, this is a standard size action with a 1" diameter barrel thread. My question is if this is large enough of a barrel shank to chamber in .577? Assuming the it was chambered for the .577-.450 (per Kirton and the extractor) the .577 case should be no more of a burden on the barrel as it is the same diameter as the .577-450 at the barrel shank.

Any insight you gentlemen can offer would be most welcome. If anyone has a falling block .577 I sure would be interested to learn the barrel shank diameter. Also, if anyone has a BP double rifle it would be instructive to learn the wall thickness of the chambers. Any information would be greatly appreciated.

Thanks!

Glenn